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rust: iommu: add device lifetime to IoPageTable

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Currently, using a raw IoPageTable is unsafe because the returned
IoPageTable is not tied to the device driver binding lifetime.

Since device drivers now receive a lifetime parameter <'bound>
representing the interval during which a device driver is bound to its bus
device, add a lifetime parameter to IoPageTable. This ensures that
the returned IoPageTable cannot outlive the bus device binding.

Also remove the option to create a page table as a device resource since
currently Devres is not compatible with resources that have a lifetime
parameter. This option can be restored once the lifetime-aware
wrapper for devres is available and if a use-case appears for it.

Suggested-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Deborah Brouwer <deborah.brouwer@collabora.com>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Joerg Roedel <joerg.roedel@amd.com>
Link: https://patch.msgid.link/20260703-pgtable_lt_b4-v3-1-e738e1f513a4@collabora.com
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
This commit is contained in:
Deborah Brouwer 2026-07-03 17:28:44 -07:00 committed by Alice Ryhl
parent 849044a381
commit 233f147985
1 changed files with 9 additions and 23 deletions
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32
rust/kernel/iommu/pgtable.rs
View File

@ -16,7 +16,6 @@
Bound,
Device, //
},
devres::Devres,
error::to_result,
io::PhysAddr,
prelude::*, //
@ -59,15 +58,16 @@ pub struct Config {
/// # Invariants
///
/// The pointer references a valid io page table.
pub struct IoPageTable<F: IoPageTableFmt> {
pub struct IoPageTable<'a, F: IoPageTableFmt> {
ptr: NonNull<bindings::io_pgtable_ops>,
_dev: PhantomData<&'a Device<Bound>>,
_marker: PhantomData<F>,
}
// SAFETY: `struct io_pgtable_ops` is not restricted to a single thread.
unsafe impl<F: IoPageTableFmt> Send for IoPageTable<F> {}
unsafe impl<F: IoPageTableFmt> Send for IoPageTable<'_, F> {}
// SAFETY: `struct io_pgtable_ops` may be accessed concurrently.
unsafe impl<F: IoPageTableFmt> Sync for IoPageTable<F> {}
unsafe impl<F: IoPageTableFmt> Sync for IoPageTable<'_, F> {}
/// The format used by this page table.
pub trait IoPageTableFmt: 'static {
@ -75,25 +75,10 @@ pub trait IoPageTableFmt: 'static {
const FORMAT: io_pgtable_fmt;
}
impl<F: IoPageTableFmt> IoPageTable<F> {
/// Create a new `IoPageTable` as a device resource.
#[inline]
pub fn new(
dev: &Device<Bound>,
config: Config,
) -> impl PinInit<Devres<IoPageTable<F>>, Error> + '_ {
// SAFETY: Devres ensures that the value is dropped during device unbind.
Devres::new(dev, unsafe { Self::new_raw(dev, config) })
}
impl<'a, F: IoPageTableFmt> IoPageTable<'a, F> {
/// Create a new `IoPageTable`.
///
/// # Safety
///
/// If successful, then the returned `IoPageTable` must be dropped before the device is
/// unbound.
#[inline]
pub unsafe fn new_raw(dev: &Device<Bound>, config: Config) -> Result<IoPageTable<F>> {
pub fn new(dev: &'a Device<Bound>, config: Config) -> Result<IoPageTable<'a, F>> {
let mut raw_cfg = bindings::io_pgtable_cfg {
quirks: config.quirks,
pgsize_bitmap: config.pgsize_bitmap,
@ -118,6 +103,7 @@ pub unsafe fn new_raw(dev: &Device<Bound>, config: Config) -> Result<IoPageTable
// INVARIANT: We successfully created a valid page table.
Ok(IoPageTable {
ptr: NonNull::new(ops).ok_or(ENOMEM)?,
_dev: PhantomData,
_marker: PhantomData,
})
}
@ -240,7 +226,7 @@ extern "C" fn rust_tlb_flush_walk_noop(
) {
}
impl<F: IoPageTableFmt> Drop for IoPageTable<F> {
impl<F: IoPageTableFmt> Drop for IoPageTable<'_, F> {
fn drop(&mut self) {
// SAFETY: The caller of `Self::ttbr()` promised that the page table is not live when this
// destructor runs.
@ -255,7 +241,7 @@ impl IoPageTableFmt for ARM64LPAES1 {
const FORMAT: io_pgtable_fmt = bindings::io_pgtable_fmt_ARM_64_LPAE_S1 as io_pgtable_fmt;
}
impl IoPageTable<ARM64LPAES1> {
impl IoPageTable<'_, ARM64LPAES1> {
/// Access the `ttbr` field of the configuration.
///
/// This is the physical address of the page table, which may be passed to the device that